Telephone-switch.



, 'P-atented July'3, 1900. o. PLUMMER & c. E MONROE.

TELEPHONE S'WiTCH;

(Application filed Jan. 4, 1900.

2 $heats$heet I.

(No Model.)

THE NORRIS Pmns 0a.. movautnqq wasumcnuu. w. c.

No. 6521922. Patented July 2, I900.

0. PLUMMEB &. 0. E. MONROE TELEPHONE SWITCH.

(Application filed Jan. 4, 1900.)

(NoModeL) 2 Sheets-Sheet 2.

U ITE STATES PATENT FFICE.

OSGOOD PLUMMER, OE WOROESTER, AND CHARLES E. MONROE, OF BOSTON, MASSACHUSETT ASSIGNORS TO FRANK 0. PLUMMER, OF

BOSTON, MASSACHUSETTS.

.TELEPHONVE-SWITCH.

SPECIFICATION forming part of Letters Patent No. 652,922, dated July 3, 1900. Application filed January 4,1900. Serial No. 308. (No model.)

To all whom it may concern.-

Be it known that we, OSGOOD PLUMMER,16- siding at Worcester, in .the county of Worcester, and CHARLES E. MONROE, residing at Boston, in the county of Suffolk, State of Massachusetts, citizens of the United States, have invented a new and A useful Telephone- Switch, of which the following is a specification.

Our invention relates to that class of telephone-switchboards which are ordinarily em-- ployed in private telephone systems Where there are a comparatively-small number'of stations, one switchboard being employed in connection with each telephone instrument; and the object of our present invention is to provide a simple, inexpensive, and efficient construction which will permit a simultaneous connection with several stations and in which the parts are arranged so that they are not liable to accidental injury or derangement.

To these ends our invention consists of the parts and combinations of parts as hereinafter described, and more particularly pointed out in the claims at the end of this specification.

In the accompanying two sheets of drawings, Figure l is a transverse sectional view of a switchboard constructed according to this invention. Fig. 2 is a partial perspective view showing the rear side of the face-plate to illustrate the manner in which a plurality of detent-strips may be connected together. Fig. 3 is a detail view of a releasing or clear ing-out button. Fig. 4 is a diagrammatic view illustrating the connections from a switchboard constructed according to this invention. Fig. 5 is a partial perspective view illustrating a modified form of detent-strip.

Fig. 6 is a transverse sectional view of the same, and Fig. 7 is a detail View of a callbutton.

In a telephone-switchboard constructed according to the present invention a plurality of circuit-making push-buttons or plungers are employed which extend through the front plate of the switchboard andmay be arranged in tiers or banks, so that any desired number of push-buttons may be embodied in each switchboard. The plunger-s or push-buttons are normally pushed outwardly by springs, a separate spring being employed for each plunger. Cooperating with each plunger are terminals or contact-fingers, preferably two such sets of contact-fingers cooperating with each plunger. The operating-piece on the plunger which controls the terminals or contact-fingers is preferably square or rectangw lar in cross-section to present a considerable wearing surface and to hold the plungers from turning or twisting. The operatingpieces are formed of hard rubber or other insulating material. The plungers are each provided with a catch or conical section, which is engaged by a detent-strip to hold the same in its operative position after being pressed in. A plurality of detent strips are employed Where more than one tier or rowof push-buttons is used, and we prefer to employ swinging or pivotally-mounted detent-strips, as we have found in practice that a swinging or piv-v otally-mounted detent-strip isfar less liable to cramp or bind than a detent-strip which is mounted to reciprocate or slide. Each plunger is also preferably provided with a conical releasing or clearing-out section, which will raise the detent-strip far enough to release all previously-actuated plungers or push-buttons when a connection is desired with a single or individual subscriber.

' Referringjto' the drawings'and in detail, the telephone-switchboard herein illustrated comprises a face-plate 10,preferabl y of metal. Extending from the rear of the face-plate 10 are posts 11, carrying cross-strips or bridges 12. Extending through the face-plate l0 and preferably arranged in tiers over each other are the push-buttons or plungers 13. Each of the push-buttons or plungers is normally forced outwardly by a coiled spring 14. The springs 14 are inclosed in sockets in the bridge-pieces 12. The sockets for receiving the springs 14 do not extend completely through the bridge-pieces, and as the bridge- 5 pieces are preferably made of hard rubber'or other insulating material the springs 14 andof motion of the plungersas, for example, pieces of solder from dropping into the path of the plungers while connecting wires to the terminals. Near their inner ends the plungers or push-buttons 13 are provided with operating-sections 15, preferably rectangular or square in cross-section. The operatingsection 15 of each plunger or push-button engages two terminals or contact-fingers 16 and.

is arranged to force the same apart to bring the contact-fingers 16 into engagement with fingers extending in from side strips or insulated combs l7.

Ve prefer to employ operatingsections 15 on the plungers which are rectangular in cross-section not only for the reason that said operating-pieces will have wearing-surfaces of considerable width, but also for the reason that the operating-pieces will prevent the plungers from being turned or rotated, so that when the parts of the switch have been once adjusted or set to exactly the proper relation the relative position of the parts will be maintained even when plungers which have been more orless sprung or are not exactly true are employed.

To hold a plunger in an operative or pushedin position, as illustrated, for example, by the middle plunger shown in Fig. 1, each plunger is provided with a catch 18 for engaging behind detent strips 19. The detent-strips 19 are mounted to swing or turn on pivots, as we have found in practice that this arrangement is more durable and can be operated with less friction than other forms with which we are familiar. Each of the plungers 13 is also provided with a clearingout or releasing section 20 for lifting the detent-strip, and releasing any of the plungers which have been previously pushed in or operated.

WVhen the push-buttons or plungers of a switchboard constructed according to this invention are arranged in tiers one over the other, the detent-strips 19 are preferably pivotally connected together-401' example, by a rod or wire 21, as illustrated in Fig. 2so that the detent-strips may be simultaneously turned or operated to release all push-buttons or plungers which may have been previously operated in the entire switchboard.

In addition to the circuit-making push-buttons or plungers we preferably employ in a switchboard constructed according to this invention a releasing or clearing-out plunger 22, (illustrated in Fig. 3,) which is of the same construction as circuit-making push-buttons or plungers, having a clearing-out or releasing section 23, but not being provided with the operating-piece or catch-section employed on the circuit-making buttons. The electrical connections from a switchboard as thus constructed are illustrated in Fig. 4-. As

shown in this figure, wires from the terminals 16 form the main line or cable L, wires from each set of terminals being carried to a telephone of the telephone system.

In the diagram shown in Fig. 4, B designates the local battery of a telephone; '1, the transmitter thereof; 0, the call-bell; I, the induction-coil; R, the receiver, and II the telephone-receiver hook, which also acts as a switch in the usual manner.

To generate a calling-current, we may employ an ordinary magneto or may take a current from a dynamo or other source, as indicated at D. The dynamo D is connected to terminals which may be controlled by a pushbutton of the same construction as the circuit-making push-button, except that the same is preferably constructed so as not to be held in or engage a detent-strip, as shown in Fig. 7. The first set of terminals (illustrated at the left of Fig. 4) are the local terminals t of the telephone instrument at the station illustrated.

\Vhen it is desired to make a call from a telephone-switchboard as thus connected, the desired push-button is pressed in, and by operating the push-button controlling the circuit from the dynamo the calling-current can be sent over the desired line.

hen the calling-current is generated by a magneto instead of a dynamo, a call may be made by pressing in the push-button of the desired telephone and then turning the magneto by hand in the usual manner. When a magneto is employed, the use of the callingbutton shown in Fig. 7 may be dispensed with.

When a call is received, the person receiving the call pushes in the plunger or pushbutton of his own instrument, and by then taking his telephone-receiver from the hook the ordinary connections will be made between the two telephone instruments. When the conversation is completed, the operator may clear his switchboard by operating the clearing-button, (illustrated in Fig. 3,) or if he desires to make any other call he may clear the board by pushing in the plunger or push-button of the station then desired to be called to the limit of its movement, so as to release the previously-operated push-button. In this manner any two instruments in the entire system may be put in circuit with each other as a pair or any number of instruments may be used in pairs at one and the same time to the limits of all the instruments in the system.

Each pair of instruments in circuit with each other will not disturb the other users, and the conversation between any pair of instruments will not be overheard or interfered with from any of the other instrumentsthat is to say, in its ordinary operation a telephone system provided with switchboards constructed according to our invention will constitute what may be considered a non-interfering system, by which we mean to signify a telephone system arranged so that any two telephones may be thrown into connection, and the connection between two such' telephones will not ordinarily be interfered ICC I more people at the same time.

with nor the conversation interrupted by other parties then using other instruments. In some cases, however, especially when telephon e-switchboards constructed according to our invention are employed in warehouses, factories, or in different parts of the same large plant, it may be desirable for a personfor example, a manager of a large plant-in issuing orders to two or more departments to be able to hold a conversation with two or Switchboards constructed according to our invention have been especially designed with a view of permitting this to be done, when desired. For example, if two parties are holding a conversation and it is desired to call in a third party, thereby changing the non-interfering into an interfering system, in which more than two persons may hear all that is passing over the line, the person desiring to call the third party will push in the desired push-button, and as this may be done without releasing or holding in the previously-operated push-buttons a person may talk with two or more persons at the same time, and more than two persons may thus be put into communication.

It the operator after having called up the third party or a person in addition to the one he was originally talkingto desires to resume a non-interfering conversation with the one first called up by him, he may cut out the third party by simply pressing in the pushbutton originally called by him to the limit of its motion, thereby releasing previouslyoperated push-buttons and permitting him to continue a non-interfering or direct conversation with a single other person-that is to say, in a telephone-switchboard constructed according to our invention if the plungers are pushed to their limits of motion the system will be a non-interfering system, in which but two instruments can be connected at one time; but, on the other hand, if the plungers are pushed but part way in a simultaneous connection may be secured between more than two telephone instruments, thus changing the system from a non-interfering to an interfering one.

In some cases instead of employing the form of detent-strip illustrated in Sheet 1 of the drawings we contemplate employing a pivoted detent-strip comprising two parallel bars or strips, and we have illustrated such a construction in Figs. 5 and 6. As shown in these figures, the detent-strip 24 comprises afront strip or bar 25 for engaging the detent-piece of the plungers anda second bar or strip 26, arranged parallel therewith, for cooperating with the releasing-sections of the plungers, and in practice we have found this to be a desirable form of construction, as the distance to which the plungers must be pushed in to effect the release of the detent-strip may be made shorter than the construction before described.

We are aware that other changes may be made in the construction of our telephoneswitchboard by those who are skilled in the art without departing from the scope of our invention as expressed in the claims. We do not wish, therefore, to be limited to the forms herein shown and described; but

What we do claim, and desire to secure by Letters Patent of the United States, is

1. As an article of manufacture, a telephone-switchboard comprising a plurality of circuit-making plungers, terminals cooperating with the plungers to form connections between telephone instruments, and a retaining device for holding the plungers in their pushed-in or operative position, whereby any desired number of plungers may be successively operated to bring a successive number of telephones into simultaneous connection, said retaining device being constructed so as to be released when one of the plungers is pushed to the limit of its travel, whereby all previously-made connections will be cut out and a connection with a single desired telephone established, substantially as described. 0

2. As an article of manufacture, a telephone-switchboard comprising a vertical faceplate, a plurality of horizontally-movable circuit-making plungers arranged in tiers over each other, springs normally forcing the plun- 5 gers outwardly, contact-arms cooperating with each plunger, a vertically-movable gravity actuated pivotally-mounted detent-strip for each tier of plungers, and a connection for simultaneously turning the detent-strips,subtoo stantially as described. J

3. As an article of manufacture, a:telephone-switchboard comprising a face-plate, a plurality of circuit-makin g plungers, springs normally forcing the plungers outwardly, an operating-piece rectangular in cross-section mounted on each of the plungers, contactarms engaging opposite faces of the rectangular operating-pieces so as to hold the plungers from turning, and means for holding the I 10 plungers in their pushed-in or operative position, substantially as described.

4. As an article of manufacture, a telephone-switchboard comprising a face-plate, a plurality of circuit-making plungers, springs I I 5 normally forcing the plungers outwardly,contact-arms cooperating with each plunger, a pivotally-mouuted swinging detent-strip, a catch-section on each plunger arranged to be engaged by the detent-strip for holding the plungerin its pushed-in or operative position,

and a releasing-section on each plunger sepa-. rate and distinct from the catch-section thereof for raising the detent-strip to release previously-actuated push-buttons, substantially 12 5 as described.

5. As an article of manufacture, a telephone-switchboard comprising a face-plate, a plurality of circuit-making plungers, each having an operating-section, a catch-section, 1 o

and a releasing-section,springs normally forcin g the plu n gers outwardly, a pivotally-mount ed swinging detent-strip cooperating with the catch and releasing sections of the plungers,

and a clearing-out or releasing push-button or plunger-arranged to lift the detent-strip when it is desired to release all previously-actuated circuit-making plungers, substantially as described.

6. In a telephone-switchboard, the combination of a face-plate 10, a plurality of circuit-making plungers 13, each having an operating-section, a catch-section, and a releasing-section, two sets of terminals cooperating with the operating-section of each plunger, springs 14 normally forcing the plungers outwardly, pivotally-mounted swinging detentstrips 19 for holding the plungers in their pushed-in or operative position, and a callbutton for throwing in a calling-circuit when desired, substantially as described.

OSGOOD PLUMMER. CHAS. E. MONROE.

Witnesses:

WILLIAM J. BALDWIN, M. E. REGAN. 

